Electromagnetically controlled fuel injection



Feb. 39, 1943. o. FUSCALDO ELECTROMAGNET I CALLY' CONTROLLED FUELINJECTION Filed Jan. 26, 1940 2 Sheets-Sheet 1 INVENTOR O/fawo Fusca/do.

(m/w, Gm-lab? ATTORNEYS Feb. 9, 1943. r 0. FUSCALDQ 2,310,773

ELECTROMAGNETICALLY CONTROLLED FUEL INJECTION Filed Jan. 26, 1940 2Shets-Sheet 2 T1 :i .4; I 57 Z9 INVENTOR 1 0/7 //0 Fusca/db BY D1 KwwwbATTORNEYS.

.Pat ented Feb. 9, 1943 ELECTROMAGNETICAILY con'rnonnm FUEL INJECTIONOttavio Fuscaldo, Milan, Italy; vested in the I i Alien PropertyCustodian I Application January 26, 1940, Serial No. 315,734

In Italy January 27, 1939 2 Claims.

This invention relates to electromagnetically controlled fuel injection,and its general object is to deliver automatically a constant air-fuelratio under all operating conditions of explosion 'engines fed byelectromagnetic fuel injection.

The mechanism of the present invention in its illustrated embodimentcomprises in combination a series of electromagnetic injectors, at leastone volumetric fuel-pump for feeding liquid fuel to said injectors, adevice for gauging the fuel-flow placed as a bypass between the suctionpipe and the pressure pipe of said pump, means for adjusting saidgauging device through a pressure responsive instrument, and means whichis controlled by the engines speed for influencing the electric circuitbreaker which controls the ener-' gizing of the winding of theelectromagnetic injector.

The invention will now be described with reference to the attacheddrawings, given solely by way of an example.

Fig. 1 is a View, substantially diagrammatic, of an embodiment of thedevice as applied to an explosion engine.

Fig. 2 is a portion of Fig. 1, showing details.

Fi 3 is a central section view of the electromagnetic injector of Fig.1.

Fig. 4 is a longitudinal central section view of the current distributorof Fig. 1; and Fig. 5 is a right end view of Fig. 4 with the cover plateomitted.

1 shows an electromagnetically controlled injector I, which may be oneof a series, energized from battery l5 and supplied under pressure fromone or more fuel pumps 5, through pipes 9. Each injector may beconstructed as in Fig. 3, wherein the solenoid winding 30, in circuitwith the battery or current source I5 can attract the spring-resistedcore 3! which pulls the injector valve and rod 32 to open the valve andcause each injection; the liquid flow and spring pressure closing thevalve when the coil circuit is broken. This construction is the subjectof copump extends a bypass passage back around the pump and adapted topermit backfiow of fuel not passing'to the valves I; and in this passageis arranged a controller 8 for varying the delivery, in-

dependently of the pump speed. Pump 5 draws the fuel from the tank Ithrough the pipe 8 and 55 sends it to the injector l or to the series ofinjectors feeding the various cylinders of the engine. The bypasscontroller or valve 6 is varied in its action by a pressure responsivedevice, as a manometric Sylphon-capsule or bellows til, the interior ofwhich is in constant communication by a small pipe H with the engineintake conduit 2|, leading to the usual inlet valves. The bellowsdevice, thus responsive to intake pressure or suction. controls thebypass 6 by means of a link l2, piv

oted to a lever I3, fulcrumed at l3, so as to reduce the fuel volumeflow, by discharging, into the inlet pipe 8 from pipe 9 in increasedfraction of the fuel pumped, with the decrease of the absolute pressureof feed-air, i. e. with the increase of suction; and vice versa. I Thetiming of current distribution to the injectors I may be by means of adistributor M of a type that contains means for varying the angularclosing time of the contacts, as for instance that shownin Figs. 4 and 5containing features disclosed in copending applications and not hereinclaimed. The distributor It has a shaft 35 which is driven from andintime with the engine shaft and carries a cam 36 of shape to swing a 7contact arm 31 in proper coordination. The arm carries an insulatedcontact 38 which is connected by a conducting strip 39 to a terminalpost 60. The strip may be also a spring pressing arm 37 to close contact38 against an opposing contact M. The cam 35 therefore causes thecontact 38 to separate from and return .to the contact 4!, to break andmake the circuit. The contact ll while relatively fixed is operativelyadjustable, for c which purposeit is mounted on an extension or' car 152outstanding from an adjustably movable plate 63. This plate may swingslightly and for convenience is shown pivoted to the same stud or pin atabout which the contact arm 31 oscillates. Adjustments of plate 43 andcontact 4! are effected by an eccentric "25 on a shaft 46, the eccentricoccupying snugly a slot in the plate. The shaft fit carries an arm 4'!for efiecting these adjustments, and this arm, as shown in Fig. 1, isadjustably swung under control from the engine speed so that the higherthe speed the longer the angular period of current flow in each cycle.

The electric current may flow through the circuit from battery l5, whenthe master switch It is closed. A centrifugal regulator ll, driven bythe engine, operates through a lever l9 and link l8 to swing-the arm llof the distributor M,

thereby to vary the angular period of closure of the contacts in eachcycle in direct relation to the speed of theengine which period istherefore made substantially constant in point of time.

It is manifest that if the angular timing of closure of the contactsremains constant at all speeds, the actual timing, or period of time,varies evidently in inverse ratio to the engine running speedsconsequently in that case an increase in speed of the engine increasesalso the fuel pressure in the injectors, as the actual time during whichthe injection is operative diminishes, while the volume flow in the pumpmust increase, the latter being of the volumetric type. Therefore, whilethe fuel feed pressure is very low at the start, it becomes very high atthe highest speeds of the engine; this causes an excessive drop in thevolumetric efficiency of said pump (because the leakage increases in allexisting gaps and crevices), and causes also a rapid wear of the pump(with consequent increase in said gapsand leakage), resulting in a greatreduction in the flow factor of the injection nozzles and a quickererosion of the. same (owing to the increase of the discharge velocity),as weli as too penetrating an injection (causing the atomised fuel tostrike against the walls and build up large drops) and a greaterdiiilculty in keeping the pipes and fixtures perfectly tight. Thesedifilculties it is an object of the present invention to overcome. r I

The inclusion of a centrifugalgovemor in the present combination ofelements substantially eliminates all of the stated inconveniences, byannulling their cause, namely the undue increase in injection pressure.In fact, while the volumetric pump'provides automatically a volume offuel which is proportional to the engine's speeds, the centrifugalgovernor provides auto-'- matically a way to maintain the time ofinjection substantially constant, so that the pressure of the fuel alsoremains constant.

The device of this invention operates as folair throttle 20 constantlyopen) are imposed by load changes,.as is the case with the power curve,the amount of fuel and of air for each feed stroke of the engine remainconstant and therefore the fuel-air ratio remains constant, -as desired.

The slight decrease in the intake of air into the cylinders whichunavoidably occurs on'increasing the speed of the engine, caused by theincrease of friction in the intake pipe 21, causes in its turn a slightincrease in the depression in-said inlet pipe and therefore also in themanometric bellows or capsule Ill, which responsively shortens and,acting on the by-pass 6 of the pmnp, causes its delivery to' decrease.

When the changes in the sp ed of the engine are brought about by changesin the volume of feed-air, through the adjusting action of the throttle20, as the case may be when working on the utilization curve, then themanometric bellows l undergoesan extreme action, because in this casethe change in the depression is very great. The more the throttle 20 isclosed, the

' tended of the variations of the absolute air lows: When changes in theengine's speed (with w feeding pressure. In order to fulfill the generalrequirement that the entire range of variation in the length of thebellows may cause in the distributor the complete range of variation inthe length of time of contact closure, it issufflcient that the bellowsshould be of proper dimensions and properly adjusted for the purpose.

Considering now the performance of the system in sudden changes ofengine speed (accelerations or decelerations) it should be noted thatupon a quick opening of the throttle, whereupon the cylinders areimmediately and completely filled with air, the fuel feed tends to lag,as it can only increase in consequence of the engine's acceleration,that is; of the pump's and governors increase. in speed. But this lag issomewhat reduced because the simultaneous decrease ing with the pipe 9..During the normal running conditions the fuel in said chamber maintainsa certain level above whichthere is a cushion of compressed air at thesame pressure. The actign of this refinement will now be explained.

Supposing the engine to be running at slow speed, on opening quickly thethrottle, the air inflow to the engine is complete and rapid as statedabove, and the reserve of fuel contained in chamber 22, urged by the airpressure above it, feeds partly into pipe 9 and so provides the fuelneeded to allow the engine to accelerate sufficiently to allow in turnthe pump to increase its delivery, while the automatic closure of theby-pass helps out. When conditions become settied the fuel reserve inchamber 22 refills auto matically and rapidly, affording a cushionedauxiliary supply.

If the air throttle be closed suddenly, what happens is that, while thefeed of the air ceases immediately and almost completely, the pumpedfuel goes on feeding in a large measure, as it with electromagneticinjection is exclusively obtained by cutting-oil the current from theinjectors. At this exact moment, the fuel pressure in the piping 9rises, because the injectors have closed, while the pump goes on runningawhile, although at a decreasing speed. In the connection from invertedchamber or flask 22 to the pipe 9 is a'cock 23 to cut of! thecommunication. Now, if at the instant the engine'stops the cock 23 isclosed, cutting oi! the communication of chamber'22 with pipe 9, it willbe possible to keep stored in thecha'mber a quantity of fuel underpressure; and this will prove useful for an easy restarting of theengine, even after a rather long stop, and without any other outsidehelp. It will be sufficient to open at the proper moment the cock 23while the engine is running only slowly, or is driven by the startingmotor, and while the pump has yet too small a. delivery for fulloperation.

It should be understood that the details of construction, arrangement,design and application of the invention may be varied in many wayswithout thereby exceeding the scope of the invention.

Having now described my invention and ho the same is to be carried out,what I claim as my invention is:

substantially steady actual time duration of each injection; anengine-driven volumetric fuel pump delivering by its pressure pipe tothe series of 1. Fuel injection apparatus for explosion engines,comprising a. series of valved fuel injectors injectors, adjustablemeans associated with the pump for modifying the rateof flow of pumpedfuel to the-injectors, and a pressure-responsive capsule instrument incommunication with and operated from the air pressure in the engineintake for adjusting said fuel-flow-modifying means and arranged toreduce the rate of fuel flow to the injectors with decrease of intakeair pressure and vice versa; whereby the fuel injected into eachcylinder in each cycle is proportioned substantially to the air inflowto maintain substantially steady the air-fuel ratio under varying intakepressures and engine speeds.

2 In an explosion engine fuel injection apparatus as in claim 1, a fuelpassage extended laterally from the pump pressure pipe, a closed fuelreserve vessel to which said passage extends adapted to containcompressed air above the reserve fuel therein, and a cock in saidpassage to shut off and isolate said vessel and contained fuel and air;whereby on stopping the enginethe cock may be closed to seal and confineunder pressure the liquid and air in the vessel, thereby to provideinitial fuel pressure by opening the cock on restarting the engine.

OTIAVIO. FUSCALDO.

